Method of making cord tires



Sept. 9, 1924.-.

G. o. KRATZ HlTflOD OF MAKING CORD nus Filed Aug- 14. 1920 2 Shuts-Sheet 1 17:00: 1

Se t. 9, 1924.

G. D. KRATZ im'ruon 0F mum coanmzus F iled Aug. 14. 1920 2 shun-shay a Patented Sept. 9, 1924.

UNITED sTArEs PATENT orifice? GEORGE n. KRATZ, or AKRON, onto; Ass enon 'ro THE FALLS nnnenncoiriraunbr t CUYAHOGA rants, 0310, A CORPORATION or can).

fri irnon or Mannie corn) TIRES.

, Application fiiaau asi i4, 1920. Serial No. 403,576.

To allcvhom it may concern:

dieit known tliatI, GEORGE D.-I{RATZ,- a citizen of the United States, and a resident of Akron, county of Summit, and State'ofi a new and useful Int Ohio, have invented provement in Methods of Making 'Gord Tires, of which the following is a specifica tion, the principle of the invention being herein explained and the best mode in which I have contemplated applying that principle,

so as to distinguish itfrom other'inventionsl The present improvements relate inore:

particularly 'to the manufacture ofcord tires constructed of so-c alled thread-fabric" or cord-fabric, i: e.- of a'fabric composed'of strong longitudinal warp threads held together by fine non-stretching, non-strengthgiving weft threads. Indeed, ordinarily such warp threads are held together simply by the film or coating of rubber which is regularlyused as a cementing or binding material to hold the several layers of the tire together? i .L In my co-pending application, filed May 26, 1919, Serial superimposed one upon the other in the'mane ner described, or that successive plies may sameangle, and

becnt' initially all at the such 'angularity subsequently modified iii cidentally to'the 'superpositionzof the plies one upon the other, in order to secure the desired effect in the composite structure The presentfimprovemeiits' have regard more particularly to this last imentioned method ofcon'structing cord tires of the type in hand, the object being to provide suit able steps and improved mechanical de vices whereby allithetplies of 'fabric' used inlthe construction of such a' tiremay be out; at the Same angle to th thread section, No. 299,87 5, I have shown and described a cord tire built up of sets of" thread or cord either be out in and then;

and then distorted to various degreesof -airs gi ilarity duringthe construction of the ,tirev itself; This procedi'ire not'only effects a great decrease in wastage inthe 'o'utting of I but also, owing to'th'e-i the application 10fvai'ious plies of fabric, mechanical features in superimposing one ply of fabric upon another, prevents the possibility ofconfusing plies of different angulariti'esgi Tothe-accomplishinentof the foregoing; and related ends, the invention," then, eons? sists ofithe steps hereinafter'full'y described" p and particularly pointed out iinjthe. claiihs,l the annexed drawings and thefollow-ing de-'- scription mechanism embodying the inventionpsuch Y but? disclosed means illustrating, however,

setting forth-in "d'etail" certain several of the various waysin which the;

principle of the invention ina-y=:befutilized or embodied.

In said annexed drawingsvz Fig 1 is aplanxview ofa Senna; tire of the type herein involved, shown for" convenience as a straight instead ofa curved away better to and with successive portions ibrolren illustrate the ai'nterior "construction thereof; Figs Q and3- are diagram;

matic views respectively illustrating the an gular relationship: of the warp threadsuina contiguous layers 'or plies of; fabricioom z posing such tire {Fig.4 shows. niyrpresent1 improved method of cutting theistripsror plies frorna sheet of fabi'ic Fig. 15 is a; view of such a strip or plyafterbeing cut' fizom the sheet; Fig; 6 is as in Fig. or stretched to give the effect of same on a diiferent sheet; 'Fig'. 7 is aplanvi'ew,andFig,8 as'id'e elevation, both m ore or; less diagraniinatic'in a suitable form of appa a strip of fabric,

character, showing ratus adapted; to apply a view of tlieisairie strip 5, but after it has been distorted cutting-tlie" angle from' the orig-inal-' such'asshown in Fig; 5-, to the tire' being built, at the desired Fig; 9 is a front elevation,

degree I of an eularityand 10 side view, of adetail f of such apparatus;

showing. a modification in construction of" same, Fig; 11 is a side elevation illustrating y. a modification of my inethod for secur ngj the same result; Figs; 12 and 133 are :pla n views corresponding with Fig 11, showing how two different degrees: of" angularity'=in the application of 'acured; and F g -i ltfi p strip or ply may be se-- ,5 "tetlp ve y v to, the

show, inside and-front elevation, a device employed in connection with theoperation illustrated in the three preceding figures.

In the illustrative construction of tire shown in F igc'l, an eight-ply tire, or rather tire shoe, is shown, the plies: or layers of fabric being arranged in three sets, each made up of a plurality of contiguous layers or plies of thread fabric.- The innermostvof these sets, as shown at the upper end of the figure sinquestion, is really aidouble set,

being-composed of four layers! or plies 1, 2,.

3,2 4, 1-the2strands in such first layer. or ply lying atvan angle of. forty-five degrees to" a median lineat or parallelto the periphery ofrthe tiret; the strands of the second layer or ply lying-at an angle of thirty degrees to such-iline; the strands of the third layer-or ply lying at an angle of forty-five degrees-to -SllClldlI18z; and 'lthe'E'strandscofthe fourth layer 'orx-ply lyingat an an 'lerof thirty degrees to such line. It will beobser'ved that inlthecase of the first two layers, inwhich the: strands respectively lie at angles of forty-five and thirty degrees to a median line at or parallel to'the periphery of the tire, any two'such strands run in the samedirection, i.. e. both lie in the quadrant formed by suclrline and a transverse line at right angles thereto and passing through the point of intersection of such strands (see Fig. 2); and that similarly in the case of the third Sand fourth layers, inwhich the strands respectively lie at forty-five and thirty degrees to a median line at or parallel thereof. 7 v

The second set of contiguous layers of fabric, asishown in Fig. l, COIIlPI'lSGSxt-WO such layers5'and 6, in thefirst of which the strands lie at an angl'eof forty-five degrees to the aforesaid' median line, and in .the second of which :thestrands lie at an angle of thirty degrees to suchl'lina the strands in.

the two layers'i'or plies running in the same direction so as to have the f relationship shown-:in'Fi gfi; The third set of contiguous layers of fabricalsocomprises but two such:

layers 7 and 8,'the relative disposition of the strands in these'layers 'being'the same as that of the strands inlayers 3 and 4. and so cor responding withthe showing in Fig; Inbetween each successive set" of such layers or plies of fabric there are preferably interposed layers9 and 10 of rubber, respectively, which function in an insulating and cushioning capacity, but these layers are not essential. The outermost or last mentioned set of layers of fabric is then covered "by the usual breaker strip 11 which is composed of a heavy gurncushion of suitably prepared rubber calendered upon an open-weave fabric, and finally the whole is covered with an outer layer 12 of rubber which constitutes the tread of the tire;

The several strips ofi'fabric which are required in constructing atire of the Ldescrip; tion just set forth, according tothepresent. invention, the originalsheet, as shown in Fig. 4-, so that wastage will be 'reducedflto a m'inimum; AS579 are all cut at the'same sum'ing the angle chosen toibe fortyafi've de grees', the typicalstrip a will thenpresent the appearance illustrated-int F 'iglf, 5,.which f strip :will obviously serve -without change} for such of the layers or plies requiredin the construction of the tire as just described,

inwhich the angularity of the strands to the median line is desiredtobe forty-five de grees, inasmuch as by simply reversing-the strip-"the strands d may be causedito runeither to the right or left of the median'line as desired.-

In order to secure angularity for thethreads' in the'st'rip as applied to the tire, from thatto which the a different degree "of strip is thusinitially cut, I nowrproceechas follows, it being understood that the present improved method isprimarily adapted to tires built upon a coreormandrel held in position and chuck, although it may be *equallywelli applied to tires built by hand. Thusinthe apparatus shown in*Figs.i 7 and8"th e-cor 15, upon which the tire is formed; is de signed to be rotated in thedirection indi+ cated by 'the'arrow,"as' the strip'd is applied thereto, or to previously applied strips form-v ing'the partially completed carcassof a tire;

rotated by a power-driven The stock'strip d, which is cut at the desired? degree'of angularity or bias from the origq inal sheet, is'spliced together so as to form" a length sulficient for 'tlierconstructionvof one or more tires. This is thenrolledon' -a shell or roller 16 with-the usual. material placed between the layers Fof rubber: coated fabric, in order'that'such layers will not; stick together. pared is J then The roll of fabric tliuszepre placed-1 in a a suitable rack? (Fig; 7) and partially unrolled',ithe line-ri e" or "other material which has beeniaplacedihetween the layers of' rubber coatedtabri being rolled up onlanother roller-1'7 asstrip; :16? The strip of (Z is unro'lled from roller" fabric itself isdrawn'over a truncated-roller: l8 and'applied to thewcore l5f where' it""is" caused to iadhere at a: given point atth'er periphery-of the tire, either 'by the-use Lof'la: rubber cement or through the adhesion of its own surface to the core or form, which is" the ply rolleddown and conformed to the corein the usual manner so as to properly shape it. p x t f i The loose end of; the strip wound on the shell or roller 16,,which has been torn free from the portion of the strip applied to thecore or form, is then drawn over a second truncated roller similar to the first bu't of difi'erent relative end diameters, and

again brought to the tireform or core and applied asfin 'thejprevious instance, after which the form isagain rotated through one revolution. The second strip or ply" of fabric thus applied, having been, drawn across a truncatedroller of difierent angular slope or bevel from that first used, the"an gularity of the threads of such second strip will: differ from that'pf the first by'gan amount dependent upon the relative pitch of the two'rollers thus; used; orinstead o'f two different truncated cones or rollers, the desired effect may be secured by employing one roller of a given angularity for the ap-- plication of the first-ply, and changing it end for end before thesecond ply is applied.

The application of two or more plies in the manner just described, bythe use of two or more rollers,'constitutes one set of'fabric plies in a tire of theconstruction heretofore described. :A second set of'fabric'pliesfor layers may then be added by drawing over the same. rollers two more strips whichhave been rolled upwithth'e warp threads cut at the sameangle as those previously employed, but at right angles to them. As already indicate d, such strip is obtained by i simply rolling up a strip as'cut from the original sheet on shell or roller 16in a direction opposite to that in which the first strip'w'as rolled up.

The placing the heads, the application of the tread, side wall, and the entire construction of the remainder of the tire, is then carried out by any of the appoved methods employed in current commercial practice.

Where a roller of truncated shape is employed, as hereinbefore described, such roller being of greater diameter at one end than at the other, stretches the strip of fabric unevenly, tending to crowd the strands together on the side of smaller diameter, and to spread them apart on the side of greater diameter. In this way the angularity of the threads in the original sheet from whichthe strip or ply was cut, may be increased or decreased by distortion, being dependent upon the relative diameters the distortion; effected of" the respective ends. of the truncated roller. It will be apparent that othermeans than such truncated roller 7 may be utilized to produce the desired distortion "inthe an gularity of the threads orl strands in such n strip. Thus such distortion 'will follow the use of any'meanswhereby one side of the strip or ply of, fabric is caused tostretch a greaterfdistancethan the other side when the force drawing the ply onto the core or form is applied",either at ia po nt -midway between its edges or across its entirewidth, I y as shown in Figs 9 and 10, in [anapparatus of the sort illustrated in Figs. 7

- Thus,

and v8, '1 may substitute for such truncated roller] a cylindrical roller divided trans versely into. two or more sections 20 and 21 which revolve at" different speeds as the ply is drawn over them. which the sections'will revolve may be con trolled by the seer any suitable tension device, such as brakebands'22 23 passing over pulleys 24,25, attache'd to'the' ends of the respective sections, weights26, 27, of different magnitude, being secured to their The relative speeds" at a free or depending'ends of said bands, where by one sectlon'or portion of the roller'asa whole is caused to revolveata difi'erent rate of speed from thatof'the portion immedi' .ately adjacent to it. 7

1: havealso found} that the same dist-or c t-ion of the threads or [strands in'the strip as it is applied fto the core may be accomplishedby sii'nply revolving the latter at different rates of speed. As illustrated in Figs. 11, 12and 13, the applicationotthe I successive "strips, or plies, andthe forming of them to the' core, is accomplished by-the use of round metal disks 30 which press the strip. to the core and which are mechan} ically operated to traverse the latter" in a radial direction from its periphery 'to the bead. -Such revolving disk, or stitcher; as it is commonly termed, is shown on; somewhat larger scale in Figsle and 15,"and is a familiar implement'or d'evicefat present employed-injthe tire makingart,'tvvo such stitcher's being'ordinarily carried on a common 'pivetauw mounted support 31'- having a handle 32, by means of which it may swung to bring either of said stitchers into contact with the corresponding sideof the tire. It is necessary to stitch down one side of a ply at a time, with the core revolving in different directions, since the threads inf such ply should run away from the stitcher; otherwise there will be a tendency for ing or wrinkling.

crowdi Thus as shown in Fig. 12, as the ply comes against the trailing. edge of the ply having regardto the angle ,of'the threads to ,the

, linein-which the plyismoving. Then'this side of .theply has been. forced against the core and completely rolled down, the direction of the core is reversedrandthestitcher handle swung. into. position Gpsoas to roll the other side of the ply-down.

Now at a stated speedaof.rotation,.such. as is- 'ordinarilyemployed, the threads of. the ply, as thus rolled down will retain practically their original angularity with respect to the median line of. the strip ofufabric composing. the .ply for-example,- anangula-rity of 45, as indicated in said l igalQ. However, -if the; core be revolved at a more rapid rate-of speed, .for. example twice as; rapidly as .inordi naryv practice, and the two; sides of the..-strip,or ply be sstitched down otherwise in the same fashion. as. just described,.- such angularity; of the. vthreads will be altered to a considerable extent, and may be changed from theoriginal 45 to approximately 30 as shown in Fig. 13. By using other rates' ofrotation any desired change in angularity, xwithin reasonable limits, ispthus obtainable. .In practice, one ply'will be rolled downor stitched to retain the normal angularity of the threads, then the next ply willhave such angularity alteredby this method,: just as in the case of the method first described above.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the steps herein disclosed, provided those stated by any-of the following claims or their equivalents be employed.

I therefore particularly point out and distinctly claim as my invention 'l. In a method of making tires. of .the character described, the steps which consist in applying circumferentially to a suitable mandrel-a strip of thread-fabric, and simul- 'taneously subjecting said stripalong one side to treatment adapted to crowd the strands of such fabric together and; along the other side to treatment adaptedto spread such strands apart, such last-mentioned step preceding any stitching of said strip 2.: In. a method of: makingtires: of the character described,.the steps whichconsist in, applying .,circumferentially to a suitable mandrel. a. strip of. thread .fabric. .held in longitudinal tension, and varyingsuchtension .between ,therespective sides of said strip whereby the. strands ofsuch fabricare crowded together along one side and spread I apart along the other: side, such lastrmefntloned step preceding any stitching of said strip.

,3. In .aumet-hodzof inaking tiresof character described, the steps which consist 4... In a method. of. .nn'akir'igv tires of the I character described, the steps Which consist 1n applying 'circumferentiallv to a suitable mandrel, a iSlJI'lP. of thread, fabric, simultaneously, sub-jectingsaid strip along one side to .treatment tending to crowd the strands of. such fabric together'and. along the otherside to, treatment tending to spread such strands. apart-,.then applying a. second strip in the, samemannerbut with theicondition asto crowding and. spreading of strands rev ersed,.and subsequently stitching said strips together.

5. In-a;.method of making tires ofgthe character. described, thesteps which consist in applying .circumferentially. to a suitable mandrel a strip of fabric, passing said'strip inadvance of its applicationhto said mandrel over meansfladapted. to vary. the'tenslon between; the two: sides of said strip,

whereby such strands are;crowded together alongone sidenand spread apartalong the other, and thenapplyinga second strip in the same manner but. with the condition as to tension reversed so as.to correspondingly reverse the condition as-to crowding and spreading of the strands therein.

Signed .by 'me, this 9th.,dayaof August, 1920. I

. GEORGE DQK'RATZ. 

